To detect whether you’re computer is running with a BIOS or UEFI, type the following command:
reg query HKLM\System\CurrentControlSet\Control /v PEFirmwareType
The following results codes are available:
- 0x1 = BIOS
- 0x2 = (U)EFI
Depending on the BIOS or EFI the hard disk partitioning will use MBR (with BIOS) or GPT (with UEFI) when installing Windows 7 /8.
More information about the difference between GPT and MBR can be found on the Wiki pages: